Given it's price I would have expected it to more firmly beat the 580, which while it does it's not quite what I was expecting. A ~50% increase over a 6970 is pretty darn good however and I think it would be a nice increase over a 6970.

However given that a slightly oc'd 580 is probably withing 10% of the 7970 I'd wait to see what Nvidia is going to offer before buying one.

I had hoped that the 7970 would offer more robust performance gains. But bearing in mind this 7970 with GCN is a new architecture etc, coupled with driver optimization/efficiencies gained in the next few versions of the drivers the gains, will probably go up.